Acrylamide analysis has become an area for expansion in recent years with the linking of the carcinogenic molecule with a number of fried or roasted foods and drinks. Tareke et al. (Tareke, et al., 2002) highlighted the potentially carcinogenic properties of the analyte combined with the levels present in foods that have been fried or baked. Analysis in industry is particularly common for coffee and fried potato chips (crisps).
Acrylamide is a very small and polar compound. Because of its polar nature it is extremely difficult to measure using techniques employed by laboratories which are normally designed for the analysis of larger more non polar compounds. Due to its high polarity and the difficult nature of the matrices many sensitive methods for acrylamide analysis in the literature involve two separate extraction procedures (one performed directly after the other) with methods being expensive, complicated and time consuming to perform. The majority of literature methods require two solid phase extractions (e.g. (Roach, et al., 2003)), one after the other, making analysis both time consuming and expensive. Other methods in the literature include relatively complicated two stage procedure for the extraction, cleanup and enrichment of acrylamide (Claus, 2005), a liquid-liquid extraction (Delatour, et al., 2004), that is time consuming and difficult to automate, and a less sensitive QuEChERS method (Pule & Torto, 2012).
Supported liquid extraction (SLE) uses the same extraction principles as traditional liquid-liquid extraction (LLE), which is based on analytes partitioning from an aqueous based matrix into a water immiscible organic solvent. The traditional LLE approach is more suited to less polar analytes that are more likely to partition out of the water based matrix into the water immiscible extraction solvent. Polar analytes are more water soluble, preferring to remain in the water phase and are more difficult to extract into the water immiscible organic solvent using LLE or SLE. Polar analytes are therefore usually extracted using a Solid Phase Extraction (SPE) approach.
According to standard method development strategies (Biotage, 2013) for Isolute® SLE+, a good choice of extraction solvent for extracting a neutral analyte is a water immiscible organic solvent in which the analyte is freely soluble, such as MTBE, dichloromethane and ethyl acetate for a polar compound. If the compound does not elute well in those solvents, it is proposed to add up to 5% of a polar modifier such as isopropanol. It is warned that the use of higher amounts of polar (water miscible) modifiers in the extraction solvent can lead to co-extraction of some matrix components.